Does an Aspirin a Day Lower Alzheimer’s Risk?

Taking a daily low-dose aspirin does not reduce the risk of mild cognitive impairment, dementia or Alzheimer’s disease in otherwise healthy elderly individuals. Findings from the ASPREE trial (Aspirin in Reducing Events in the Elderly) were published March 25, 2020 in the journal Neurology.

ASPREE followed 19,114 people ages 65 to 98 for at least 3.6 years and up to 5.7 years. Participants were randomly divided into two groups that received either a 100-mg dose of aspirin or placebo pill daily. At the end of the study, similar numbers of people in both groups reported memory problems, had dementia, or were classified as having probable Alzheimer’s disease.

“ASPREE is a very well-designed study that attempted to address the vascular components of Alzheimer’s,” said Howard Fillit, MD, Founding Executive Director and Chief Science Office at the Alzheimer’s Drug Discovery Foundation. “The thinking was that aspirin could reduce the risk of dementia, or at least slow its progression, because it reduces inflammation, and prevents blood clots, which can lead to dementia-causing strokes.”

While the study did not find the hoped-for positive effect of taking aspirin daily, Dr. Fillit said, ASPREE importantly increases the focus on finding therapies for vascular problems that contribute to cognitive decline and dementia in old age. Up to 50% of people have “mixed” dementia in which vascular components are accompanied by classic Alzheimer’s pathology, such as the hallmark amyloid plaques and tau tangles in the brain.

Certain vascular risk factors, such as hypertension and diabetes, are known to increase the risk of dementia and some trials have shown positive impact of addressing them. For example, recent findings from the SPRINT MIND trial showed that aggressive blood pressure lowering to a systolic pressure of under 120 mmHg (the “upper” number in a blood pressure reading) reduces the risk of mild cognitive impairment. The study did not show a connection between lowering blood pressure and reducing the risk of dementia, but investigators think this may be because the trial did not run long enough to demonstrate an effect. A two-year extension of the trial is ongoing with results expected after its completion in 2022. There are also several clinical trials ongoing looking at the effect of anti-diabetic drugs on Alzheimer’s.

“We need to continue researching the many factors contributing to dementia including vascular problems, inflammation, genetic mutations, protein abnormalities and other malfunctions common in the aging population,” said Dr. Fillit. “Like other diseases of aging, such cancer and diabetes, the answer likely lies in a combination treatment approach and information from comprehensive, long trials like ASPREEE provide us with important insights.”